Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT FUSE (E/G RM-IG1-1)

Remove the E/G RM-IG1-1 fuse from the engine room No 2 relay block.

Measure the resistance according to the value (s) in the table below.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
E/G RM-IG1-1 fuse	Always	Below 1 Ω

NG: REPLACE FUSE

OK: Go to next Step

CHECK HARNESS AND CONNECTOR
1. Turn the power switch ON (READY)
2. Check the indication condition of the PS warning light by wiggling the power steering ECU connector and wire harness up and down, and right and left.
  OK: PS warning light indication condition does not change.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next Step

CHECK CAN COMMUNICATION SYSTEM

Using the Intelligent tester or Techstream, check for DTCs and confirm that there are no problems in the CAN communication system (see DIAGNOSIS SYSTEM ).

Result

RESULT CHART

DTC Condition	Proceed to
DTC is not output	A
DTC is output	B

B: GO TO CAN COMMUNICATION SYSTEM (DIAGNOSTIC TROUBLE CODE CHART) (See DIAGNOSTIC TROUBLE CODE CHART )

A: Go to next Step

CHECK ELECTRONICALLY CONTROLLED BRAKE SYSTEM

Using the Intelligent tester or Techstream, check for DTCs and confirm that there are no problems in the electronically controlled brake system (see DTC CHECK / CLEAR ).

Result

RESULT CHART

DTC Condition	Proceed to
DTC is not output	A
DTC is output	B

B: GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM (DIAGNOSTIC TROUBLE CODE CHART) (See DIAGNOSTIC TROUBLE CODE CHART )

A: Go to next Step

CHECK HARNESS AND CONNECTOR (POWER STEERING ECU - BATTERY AND BODY GROUND)

Disconnect the A44 ECU connector

Measure the voltage according to the value (s) in the table below

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Switch Condition	Specified Condition
A44-9 (IG) - Body ground	Power switch ON (IG)	11 to 14 V

Measure the resistance according to the value (s) in the table below

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
A44-5 (PGND) - Body ground	Always	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 1: Identifying Harness Connector A44 (Power Steering ECU)

OK: Go to next Step

REPLACE POWER STEERING ECU
1. Replace the power steering ECU (see REMOVAL ).
2. After replacing the power steering ECU, check the illumination condition of the combination meter's PS warning light.
  OK: PS warning light is illuminated when power switch is ON (IG), and goes off when power switch turned from ON (IG) to ON (READY).
  
  NOTE: If replacing the power steering ECU, initialize the rotation angle sensor value and calibrate the torque sensor zero point (see CALIBRATION ).
NG: GO TO METER / GAUGE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) (See HOW TO PROCEED WITH TROUBLESHOOTING )

OK: END